Gain invariant impedance feedback amplifier

摘要

A system includes a weighting element, a transconductance circuit, a feedback loop, and an auxiliary loop. In some implementations, the transconductance circuit may accept an input and provide a first portion of an output for amplification at a variable amplification level to generate an amplifier output. The feedback loop may provide a portion of the amplifier output as a first feedback to the input. The first feedback may be associated with an impedance that may vary with the amplification level. The auxiliary loop may provide a second feedback to the input to reduce the dependence of the impedance on the amplification level.

主权项

1. A system, comprising:
a transconductance circuit comprising an input and a first output; a weighting element coupled to the first output, the weighting element comprising:
a first path configured to produce an amplifier output responsive to the first output; anda second path configured to split off an auxiliary portion of the first output; a feedback loop comprising a variable impedance configured have a dependence on an amplification level of the amplifier output, the feedback loop configured to provide a first portion of the amplifier output as a first feedback to the input responsive to the variable impedance; and an auxiliary loop configured to:
accept the auxiliary portion of the first output; andreduce the dependence of the variable impedance responsive to the amplification level by providing, to the input, a second feedback dependent on the amplification level and responsive to the auxiliary portion.